Compared with the first-generation semiconductor Si and the second-generation semiconductor GaAs, GaN semiconductor devices are more suitable for the preparation of high-temperature, high-voltage, high-frequency and high-power electronic devices due to their remarkable advantages of large bandgap width, high electron mobility, high breakdown field strength, high-temperature resistance and the like, and thus exhibit great application prospects.
GaN semiconductor devices usually operate in high-power and high-current environments. Due to their operating conditions, a large amount of heat will be generated within active areas of the GaN semiconductor devices, and as a result, the temperatures of the devices rise. The rise in temperature will result in performance degradation or even failure of the GaN semiconductor devices. Thus, usually, the heat dissipation issue should be considered in design of the GaN semiconductor devices. For an existing GaN semiconductor device, heat dissipation is realized mainly by the following approaches: heat in the active area is diffused to a device substrate and then longitudinally transferred to a base having good heat dissipation performance through the device substrate; heat is transversely transferred to the outside of the active area via metal electrode connecting lines and semiconductor material of the device; and heat generated in the GaN semiconductor device is dissipated by air on an upper surface of the GaN semiconductor device.
However, the packaging of the GaN semiconductor devices causes low air flow inside the housing, and thus results in poor heat dissipation effect by air. Since the contact areas between the metal electrode connecting lines and the GaN semiconductor devices are small, no effective heat dissipation is ensured. Accordingly, the heat dissipation performance of the existing GaN semiconductor devices is limited.